Self-lubricating pipe joint seal with rupturable membrane

ABSTRACT

A pressure responsive pipe joint seal for sealing connecting pipe joint members includes sealing flanges which define upwardly, outwardly and downwardly curved upper surfaces so that there is less tendency for them to get caught on a pipe joint member as adjacent members are slid into coupling relationship. The seal includes an inflatable bladder whereby the seal can be inflated after it is in its operative position. In one embodiment disclosed, the seal includes a cavity containing a lubricant, the cavity being covered with a rupturable membrane such that when pipe joint members are joined together, the membrane ruptures releasing the lubricant.

This is a division of copending application Ser. No. 113,358, filed Jan.18, 1980, and now U.S. Pat. No. 4,296,933, which was a division of priorapplication Ser. No. 40,273, filed May 17, 1979, and now U.S. Pat. No.4,209,179.

BACKGROUND OF THE INVENTION

In joining pipe sections so that fluids contained in the pipe will besealed therein, various sealing joints have been utilized. The mostcommon sealing joint comprises an "O" ring which is secured over themale projecting end of a pipe which is subsequently inserted into acorresponding female end of an adjoining pipe or coupler. In a similarstructure, a separate male coupler has "O" rings inserted over each ofits ends and is inserted between two female ends of adjoining pipes.

One problem encountered at pipe joints is the leakage of water or fluideither outwardly from the inside of the pipe to the outside thereof orinwardly from the outside of the pipe to the inside thereof. In waterlines, the water inside the pipe is usually under pressure and there isa tendency for such water to leak through the joints to the exterior ofthe pipe. In sewer and drain lines, there is a tendency for ground waterto build up around the pipe and leak inwardly into the sewer system.This type of leakage is undesirable in that it floods the sewer withdrain water and hampers the sewer in performing its intended function.

Sealing members have been devised which respond to increases in internalor external pressure to effect a tighter seal. One type of sealcomprises basically an "O" ring which includes an inner, annular slottherein so that fluid in a water pipe tends to flow into the interior ofthe seal and expand it outwardly. Another type of seal includesprotruding flanges which are forced outwardly against the surfaces theyabut in response to increases in internal or external pressure.Unfortunately, such flanges tend to get hung-up on one pipe joint memberas it is being slid onto another pipe joint member, thereby causing theentire seal to be moved out of its proper place. This fouls thesealability of the entire joint.

To help prevent seals from dragging on a pipe joint member as it isslipped over another pipe joint member, workmen typically lubricate theseal with some type of grease. While this is helpful, it is a messy andtime-consuming operation which unduly adds to the cost of constructing apipe line.

SUMMARY OF THE INVENTION

In the present invention, a pipe joint seal is provided which includes abase and at least one projecting sealing flange which curves upwardly,outwardly and then downwardly from the base to define a curved uppersurface over which a pipe joint surface can slide during the coupling ofadjacent pipe joint members. In this way, there is much less tendencyfor the flange to be caught by a pipe joint member during coupling andthere is accordingly much less tendency for the seal to become fouled.Preferably, the seal is used in conjunction with a coupling collarhaving a channel therein for receiving the seal. The sealing flangeextends downwardly from its uppermost point to a point at which itsexposed edge is below the level of the channel, thereby furtherminimizing the chances of the seal being caught and fouled.

In another aspect of the invention, the seal includes an inflatablebladder so that the seal can be inflated after it is in its operativeposition between two pipe joint members. This provides further insuranceagainst leaking as a result of either internal or external pressure.

Finally, in yet another aspect of the invention the seal includes acavity for containing a lubricant and means associated with the cavityfor releasing the lubricant as one pipe joint member is slid over theseal and the pipe joint member in which the seal is contained. In thisway, the costly hand greasing operation which pipe line contractors mustnow utilize is eliminated.

These and other aspects, features, objects and advantages of theinvention will be more fully understood and appreciated by reference tothe written specification and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary, perspective view of a pipeline joint withportions thereof cut away;

FIG. 2 is an enlarged view of the encircled area II of FIG. 1;

FIG. 3 is an enlarged partial view of the coupler seal and pipe of FIG.2 as the coupler and pipe are being joined;

FIG. 4 is a view of the coupler seal and pipe of FIG. 3 after the pipehas been sealably mounted on the coupler;

FIG. 5 is the sealably mounted pipe joint of FIG. 4 with the sealdeformed by fluid pressure from outside the pipe;

FIG. 6 shows a method of inflating the seal of FIG. 5;

FIG. 7 is a enlarged cross-sectional view of a seal comprising alubricant-containing cavity covered by a rupturable membrane; and

FIG. 8 is a perspective view of the pipe joint seal.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings and in particular to FIG. 1, a pipe joint 1 isformed by joining two male ended pipe sections 2 and 3 by means offemale coupler 4 which slidably receives the protruding ends of the pipesections 2 and 3. Since pipe sections 2 and 3 and coupler collar 4 allform the joint 1, they are each considered hereinafter to be a pipejoint member, it being understood that other pipe joints might utilizeother combinations of pipe joint members. Two annular seals 10, whichextend circumferentially along the interior of coupler 4 in channels 4athereof (FIG. 2) act to seal the pipe joint 1 so that external fluidsmay not leak into the pipeline nor can internal fluids leak out from thepipeline.

Referring to FIG. 2, seal 10 which is preferably comprised of aflexible, resilient material, is generally triangular in cross sectionalshape with flared sealing flanges 11 and with a flat seating base 10awhich rests against coupler 4 along the bottom of channel 4a. As seen inFIG. 3, seal 10 comprises a hollow central area 13 which is formed bybase 10a and the upwardly directed side walls 10b. Curved sealingflanges 11 extend outwardly from apex 10c formed by side walls 10b.

As seen in FIG. 3, as pipe section 2 is slidably joined with coupler 4,the outwardly curved sealing flanges 11 engage pipe 2 along its insidesurface 2a. As seen in FIG. 4, seal 10 is generally compressivelydeformed when the coupler 4 and the pipe 2 are in the joint-formingconfiguration. By such deformation, base 10a of the seal 10 is closelypressed against the bottom of channel 4a so as to prevent passage offluids along channel 4a. Also, flanges 11 are compressed and slightlyflattened against surface 2a of the pipe 2 so as to prevent passage offluids along surface 2a and thus seal the pipe joint 1.

As can be seen in FIG. 5, the generally circular-shaped area 10denclosed and formed between the upwardly extending seal walls 10b andflanges 11 acts to distribute the fluid pressure (shown by the arrow)against walls 10b and flanges 11. Because the pressure-exposed surfacearea of the seal is greatest around 10d, the fluid pressure outwardlydirects the flanges 11 forming a tighter seal against the inside surfaceof pipe 2. Further, the fluid pressure downwardly directs side walls 10bwhich act to push base wall 10a securely into the bottom of channel 4aforming a tighter seal there.

The pressure response of the flange 11 and side wall 10b on one side ofthe generally symmetrical seal does not prevent a similar response fromthe other side to fluids seeking entry into the joint 1 from that side.It is of particular importance to note, that the greater the forcesexerted by fluid pressure seeking to move into joint 1, the stronger theseal formed by flange 11 against surface 2a of the pipe will be.Similarly, the stronger the seal formed by base 10a against the bottomof the channel 4a of the coupler will be.

As shown in FIG. 6, the hollow area 13 housed in the interior of seal 10and formed therein by base 10a and side walls 10b serves as aninflatable bladder. Preferably as shown, the seal is comprised from aninflatable expandable material so that the hollow area 13 will hold theinflating substance when inflated. If desired, a separate bladder or abladder membrane may be incorporated into the seal 10 to facilitateinflation of it.

The coupler 4 comprises a needle valve 21 through which a hypodermicsyringe 20 may be inserted to inflate hollow area or bladder 13. Theneedle valve 21 is a small rubber plug secured in the coupler 4 toextend radially inward so as to generally coincide with the center ofchannel 4a. The needle valve 21 may be comprised of any suitable needlevalve material and as shown is similar to the assembly utilized to fillplaying balls with inflatable bladders, e.g., footballs or basketballs.

As bladder 13 is filled with compressed air or another inflatingmaterial, flanges 11 are pressed into surface 2a and base 10a is pressedinto the bottom of channel 4a without the additional need of fluidpressure on elements 11 and 10b. The combined sealing effect ofexpanding the seal by inflating the bladder and the pressure response ofthe flanges and side walls of the seal act to form an exceedinglyleak-and-contamination resistant joint. It should be noted, that bladder13 may not only be inflated with fluids, e.g., air, but also may beinflated with various flowable materials.

In another embodiment of this invention, shown in FIG. 7, the seal 10comprises a reservoir 31 containing a lubricant. The reservoir 31 isformed by a membrane 30 attached to the seal 10 between the flaps 11 toform a lubricant-containing cavity directly above the apex 10c of theseal 10. The membrane 30 extends circumferentially around the seal 10and contains lubricant in cavity 31 throughout the circumference.Membrane 30 is adhered to the tops of flanges 11 by adhesive or by heatsealing. As shown membrane 30 is rupturable and serves as a means forreleasing the lubricant. The membrane 30 may be comprised of anysuitable material which will be torn from the flanges 11 or itself beruptured by contact with the edge or inside surface of an adjoining pipesection.

When utilizing the seal of FIG. 7 in a pipe joint such as that shown inFIG. 1 above, seal 10 is placed in the coupler 4 as shown in FIG. 3. Asthe pipe 2 and the coupler 4 are joined, the inside surface 2a of pipe 2contacts the membrane 30 and either tears the membrane to releaselubricant or disengages the membrane 30 from flange 11 to release thelubricant.

It will be apparent to one skilled in the art, that thelubricant-containing reservoir could be a sponge-like or porous materialrather than a cavity as shown. Also, other suitable means to release thelubricant from the cavity could be utilized in this seal.

As is readily apparent by the above description, the pressure-responsiveseal described above may be utilized with various type joint structures,for example, pipes 2 and 3 could comprise female members on their insections which are inserted onto a male-type coupler. Such a structurewould comprise two seals in a manner similar to the embodiment shown inFIG. 1 with the seals mounted in channels in either the pipe sections orthe coupler. Also, pipe sections which comprise joints consisting ofsingle seals would also be suitable with the pressure-responsive seal ofthis invention. Other joints, utilizing the seal of this invention wouldbe readily apparent to those skilled in the art.

It will be understood that various changes in the details, materials,steps and arrangements of parts which have been herein described andillustrated in order to explain the nature of the invention, may be madeby those skilled in the art within the principle and the scope of theinvention as expressed in the appended claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A self-lubricating pipejoint seal fitting between and sealing connecting pipe joint memberswhich are slid into each other to form a pipe joint comprising: areservoir means in said seal for containing a lubricant; and means forreleasing said lubricant from said reservoir means as said pipe jointmembers are slid into each other to form said pipe joint, said pipejoint seal being annular and said reservoir means comprising a cavitythat extends generally circumferentially around said seal and containssaid lubricant therein and wherein said means for releasing saidlubricant from said cavity comprises a rupturable membrane on saidcavity, said membrane being ruptured and releasing said lubricant fromsaid cavity as said pipe sections are slid into each other to form saidpipe joint.
 2. The pipe joint seal of claim 1 comprising: an annularbase member and oppositely, upwardly outwardly curved sealing flanges onsaid base member defining said cavity therebetween; and said rupturablemembrane being suspended between said sealing flanges.
 3. The pipe jointseal of claim 2 wherein said base member comprises an expandableinflatable bladder, said bladder when expanded acting to tighten saidsealing flanges and said base member against said pipe sections toprevent fluid flow through said pipe joint.
 4. A self-lubricating pipejoint seal fitting between and sealing connecting pipe joint memberswhich are slid into each other to form a pipe joint comprising: areservoir means in said seal for containing a lubricant; and means forreleasing said lubricant from said reservoir means as said pipe jointmembers are slid into each other to form said pipe joint, and whereinsaid means for releasing said lubricant comprises a rupturable covermeans on said reservoir means.